Impact of a quality improvement project to reduce the rate of obstetric anal sphincter injury: a multicentre study with a stepped‐wedge design

Objective To evaluate the impact of a care bundle (antenatal information to women, manual perineal protection and mediolateral episiotomy when indicated) on obstetric anal sphincter injury (OASI) rates. Design Multicentre stepped-wedge cluster design. Setting Sixteen maternity units located in four regions across England, Scotland and Wales. Population Women with singleton live births between October 2016 and March 2018. Methods Stepwise region by region roll-out every 3 months starting January 2017. The four maternity units in a region started at the same time. Multi-level logistic regression was used to estimate the impact of the care bundle, adjusting for time trend and case-mix factors (age, ethnicity, body mass index, parity, birthweight and mode of birth). Main outcome measures Obstetric anal sphincter injury in singleton live vaginal births. Results A total of 55 060 singleton live vaginal births were included (79% spontaneous and 21% operative). Median maternal age was 30 years (interquartile range 26-34 years) and 46% of women were primiparous. The OASI rate decreased from 3.3% before to 3.0% after care bundle implementation (adjusted odds ratio 0.80, 95% CI 0.65-0.98, P = 0.03). There was no evidence that the effect of the care bundle differed according to parity (P = 0.77) or mode of birth (P = 0.31). There were no significant changes in caesarean section (P = 0.19) or episiotomy rates (P = 0.16) during the study period. Conclusions The implementation of this care bundle reduced OASI rates without affecting caesarean section rates or episiotomy use. These findings demonstrate its potential for reducing perineal trauma during childbirth. Tweetable abstract OASI Care Bundle reduced severe perineal tear rates without affecting caesarean section rates or episiotomy use.